1. Step-by-Step Tutorial NEXTA: Simulation Data Visualizer for TRANSIMS
NEXTA: Network EXplorer for Traffic Analysis
Sponsored by
Federal Highway Administration
Developed and Prepared by
Dr. Xuesong Zhou, Univ. of Utah
Freeware can be downloaded at

2. Sample Occupancy Plot

3. Sample Vehicle Snapshot Plot

4. Sample Bottleneck Snapshot Plot

5. Sample Travel Time Contour (Accessibility) Snapshot Plot

6. Tutorial Outline Network and control data visualization
View node and link properties, lane configuration
Configure dynamic project menu
Time-dependent simulation data visualization
View cell occupancy, speed, queue length and vehicle locations, MOE profiles
Other tools
Find multiple paths
Create nodes and links (in development)

7. Step 0: Create a Project File
Project file (*.tsp) is used by NEXTA to locate the folder of a TRANSIMS project

8. Inside a *.tsp Project File
First line should have the relative location of the microsimulation control file
Example: TestNet data set setup\master\Microsimulator.ctl
Example: Alexandria data set
setup\control\Microsimulator.ctl

9. Step 1: Open a Project
If the specified microsimulation file is not found in tsp file, the user will be provided with an option to manually load the microsimulation control file, or use the default input file locations

11. Step 1: Open a Project  Select iteration number
A user can specify an iteration number for loading average link performance, cell occupancy and vehicle snapshot data.
By default, NEXTA automatically identifies and loads the maximum (i.e. the last) iteration number, if multiple iterations of simulation results are available from those files stored in folder “\\results”.

12. Step 1: Open a Project  Define Loading Time Window
For (memory-consuming) cell occupancy and vehicle snapshot data, a user can specify “Start Time” and “End Time” to define a data loading time window to reduce required memory for the GUI program.
For link performance data such as density, speed and queue length, NEXTA loads 24 hours of simulation data automatically.

13. Input Files Folder Network
Node.txt, Link.txt, Pocket_Lane.txt, Shape.txt, Zone.txt
Signalized_Node.txt, Timing_Plan.txt, Phasing_Plan.txt
Folder Results
Performance.txt (density, speed, queue)
Occupancy_Avg.txt (cell occupancy)
Snapshot.txt (vehicle locations)
Remarks: A test data set with the above files can be downloaded at
A user can execute /setup/runall.bat to generate those files

14. First Look View Tools Distance Move Network Pan Zoom In Zoom Out
Show Entire Network
Show/Hide Grid
Show/Hide Node
Show/Hide Zone

15. Step 2: Zoom In -> View Lane Configuration
Zooming can also be accomplished with the Page Up / Page Down keys, the + / - keys or the mouse wheel.

16. Step 3: Double-Click a Node to Show Node and Control Properties

17. For link 110->105, there are three movements with traffic volume: movement 110->105->104 has 326 vehicles with 729 seconds of average delay, movement 110->105->101 has 323 vehicles with 690 seconds of average delay, and movement 110->105->106 has 896 vehicles with 609 seconds of average delay

18. Step 4: Single-Click a Link to Show Shape Points

19. Step 5: Double-Click a Link to Show Link Property

20. Step 6: Find Node / Find Link / Measure Distance

21. Step 7: Change Color Preferences for Background and Link Types

22. Step 8: View Text File
NEXTA fetches input file names directly from the microsimulator control file.

23. Step 9: Select Display Mode to View Simulation Results
Occupancy, Speed, Queue, Vehicles, Volume, Single Vehicle, Travel Time Contour

24. Cell-based Occupancy (I)

25. Cell-based Occupancy (II)

26. Cell-based Occupancy (III)

27. Cell-based Occupancy (IV)

28. Speed

29. Queue Length
Queue length = average number of stopped vehicles per lane * 7.5 meters

30. Vehicle
Vehicle locations are imported from snapshot file

31. Travel Time Contour
When the display mode is set to Travel Time Contour Display Mode, the minimum path travel times between a designated destination and other nodes can be plotted on the network window.
A user can right-click a node to select menu “Define Destination to Calculate Travel Time Contour”.

32. Travel Time Contour
The minimum path travel times between a designated destination and other nodes are plotted on the network window.

33. Travel Time Contour
The numbers on a node indicates the calculated minimum path travel time (in minutes) between the current node to the designated destination.

34. Travel Time Contour
A user can also customizes the thresholds of travel time categories displayed in travel time contour by selecting menu -> View -> Change LOS Interval in Travel Time Contour.

35. Step 10: Show Simulation Results at a Given Time
Simulation Time Clock: 1 hour: 33 min
Clock Bar
Slider
Drag the slider of the clock bar to view simulation results at a given time of simulation horizon

36. Go to First Minute with Vehicles
A user can set the slider of the clock bar at the first minute with vehicles.
A snapshot file might only cover a short time period of the entire simulation horizon.
After a TRANSIMS project has been loaded, a user can click on menu->View ->Go to First Minute with Vehicles to jump to the first time stamp with snapshot data.

37. Step 11: Play Animation
Rewind, play, pause, stop
Remarks: Simulation clock is advanced at 1-min interval

38. Step 12: Double-Click a Link to Show MOE Profile
Upstream node -> Downstream node (# link ID)
Green line indicates the current simulation time
Time axis (unit: min)

39. Step 13: Configure MOE Display Dialog
MOE: Density, Speed, Queue Length, Volume
Start Time, End Time, Max Y
Background color

40. Step 14: Multi-link Comparison
Select multiple links (by using Ctrl+ mouse click) to display MOE time profiles simultaneously for multiple selected links, in the same or different projects.
Data can be exported to a CSV file

41. Step 15: Find Paths Select an origin node,
Right-click to select menu “Define Origin to Find Shortest Path”,
Select a destination node,
Right-click to select menu “Define Destination to Find Shortest Path”.

42. Step 16: Show Multiple Paths
Path 1: 15 min Path 3: 18.6 min
The path finding algorithm uses dynamic travel time calculated from simulated link speed at a given time.

43. Step 17: Create Nodes/Links
Insert node (in the middle of a link)
Add one-way link
Add two-way link
Add zone
Add stop sign
Add yield sign
Add pre-timed controller
Add actuated controller
Select link type

44. Step 18: Show Bottleneck Information
A user can click on menu View->Bottleneck Info-> Bottlenecks to display bottleneck information on different links.

45. Step 18: Show Bottleneck Information

46. Step 19: Sort Link Performance Data
A user can click on menu Project->Sort Link Performance Data to sort, display and export the link performance data in a designated time window.
Select an MOE

47. Step 20: Sort Movement Performance Data
A user can click on menu Project->Sort Movement Performance Data to sort, display and export the intersection movement performance data in a designated time window.
Select a Field

48. Step 21: Reload Simulation Data with Selected Files
As there might be multiple snapshot files for the same simulation run, a user can click on menu ->File->Reload Simulation Data with Selected Files to reselect the simulation files to be loaded.
A user can select the snapshot, performance, and average occupancy files of a designated simulation run individually.

49. Future Development Save network data Run simulation directly
Configure simulation scenarios
Use vehicle trajectory information
Enable travel time reliability analysis
Enable impacted vehicle analysis
Identify traffic bottlenecks through vehicle trajectory file